The effectiveness of intravenous ketamine in adults with treatment-resistant major depressive disorder and bipolar disorder presenting with prominent anxiety: Results from the Canadian Rapid Treatment Center of Excellence

Adults with treatment-resistant depression or bipolar disorder who also have high anxiety show greater improvement in depressive and anxiety symptoms after intravenous ketamine treatment than those with low anxiety. Among 209 patients receiving four ketamine infusions, the 94 with anxious-distress had a significantly larger drop in depression scores and a greater reduction in anxiety symptoms after three and four infusions. Both groups experienced a significant decrease in suicidal thoughts. The findings suggest that ketamine may be particularly effective for people with treatment-resistant mood disorders and prominent anxiety.

Study at a glance

Abstract

Background: Individuals meeting criteria for treatment-resistant depression (TRD) are differentially affected by high levels of anxiety symptoms. Aims: There is a need to identify the efficacy of novel rapid-onset treatments in adults with mood disorders and comorbid anxious-distress. Methods: This study included patients with treatment-resistant major depressive disorder (MDD) or bipolar disorder (BD) who were receiving intravenous (IV) ketamine treatment at a community-based clinic.Anxious-distress was proxied using items from the Quick Inventory of Depressive Symptomatology–Self Report 16-item (QIDS-SR 16 ) and Generalized Anxiety Disorder 7-item (GAD7) scales. The difference in QIDS-SR 16 total score, QIDS-SR 16 suicidal ideation (SI) item and GAD7 score were analyzed between groups. Results: A total of 209 adults with MDD ( n = 177) and BD ( n = 26) were included in this analysis. From this sample, 94 patients (mean = 45 ± 13.9 years) met the criteria for anxious-distress. Individuals meeting the criteria for anxious-distress exhibited a significantly greater reduction in QIDS-SR 16 total score following four infusions ( p = 0.02) when compared with patients not meeting the anxious-distress criteria. Both anxious-distressed and low-anxiety patients exhibited a significant reduction in SI ( p < 0.0001) following four infusions.Finally, there was a significantly greater reduction in anxiety symptoms in the anxious-distress group compared with the non–anxious distress group following three ( p = 0.02) and four infusions ( p < 0.001). Conclusion: Patients with TRD and prominent anxiety receiving IV ketamine exhibited a significant reduction in depressive, SI and anxiety symptoms.